What Is A1C?

Medically reviewed by Steffini Stalos, DO

The hemoglobin A1C (HbA1C), or A1C, test measures your average blood glucose for the past two to three months using percentage values. Hemoglobin is a protein in red blood cells (RBCs) that glucose attaches to. Higher blood glucose, or blood sugar, can result in a higher percentage of glucose-covered hemoglobin and a higher A1C.

Healthcare providers usually do this test to diagnose diabetes or identify prediabetes and also to monitor the blood glucose in patients with diabetes. Learn more about HbA1C, including what normal values are, what can cause high values, and what healthcare providers recommend for lowering the A1C values.

Why Would You Need an A1C Test?

HbA1C testing can help a healthcare provider determine if a person has type 2 diabetes or prediabetes. Your blood sugar may be high due to the body's inability to make enough of the hormone insulin or use insulin properly. When this happens, blood sugar remains in your bloodstream—possibly indicating type 2 diabetes if it's too high or prediabetes if your blood sugar levels are only higher than normal.

A provider may also use it for the long-term management of diabetes. They may recommend how often you need the test—at least twice yearly—to get an idea of how well your diabetes treatment is working. You might need more frequent testing when treatment goals are not met or changes in treatment occur.

Understanding Your A1C Levels

In general, A1C level results are as follows concerning a diabetes diagnosis:

• Normal: Lower than 5.7%

• Prediabetes: Equal to or between 5.7% and 6.4%

• Type 2 diabetes: 6.5% and higher

Initial testing may be done twice to confirm the A1C results except if there are additional symptoms of diabetes. Also, the target HbA1C levels depend on several factors including the person's age, types of diabetes, and overall health of the individual. A level of less than 7% is the goal for the majority of adults with diabetes.

However, a healthcare provider decides what your target A1C values will be, so you'll work with them to find a plan that best suits you. If A1C levels fluctuate significantly, it could indicate issues with hypoglycemia, or low blood sugar, in some people with diabetes.

Maintaining an A1C that falls between 7% and 8% may be recommended for individuals with:

• Advanced diabetes complications like heart disease or nerve problems
  

• A limited life expectancy

• An inability to sense hypoglycemia called hypoglycemia unawareness

• Long-term diabetes and have had difficulty reaching goals

• Severe hypoglycemia

Factors That Can Affect Your A1C

Several factors can affect an A1C test. Exercise, pregnancy, stress, illness, and changes in eating patterns over a number of days can affect the A1C testing.

As the test measures the glucose attached to hemoglobin, any changes in hemoglobin, RBCs, or RBC numbers may affect the test results. Those changes might be due to:

• Blood transfusion

• Hemodialysis—a process where blood is filtered through a machine when kidneys have failed

• Recent blood loss

• Sickle cell disease or thalassemia—an inherited blood disorder where the body doesn't make enough hemoglobin
  

How To Lower Your A1C

The goal of lowering the A1C levels will vary from person to person based on the condition. It's vital to discuss and determine your treatment plan with the guidance of a healthcare provider. Managing your A1C levels can be complex and involves managing your diet, exercise, and medication.

Engage in Physical Activity

Physical activity has long been recommended in patients with diabetes to control their blood sugar levels—especially in people with type 2 diabetes. Regular exercise can help decrease A1C because exercise can increase your body's sensitivity to insulin. This can result in lowered blood sugar for 24 hours or more after a completed workout.

It's also helpful to mix various exercise types; aerobic exercises—or cardio exercises—are beneficial, but so are resistance or strength training exercises. Increased muscle mass from doing resistance training workouts can boost insulin activity like cardio workouts do.

Exercise recommendations for adults vary. However, they generally include doing at least 150 minutes of cardio and two days of strength training. Talk with a healthcare provider to determine what types of exercise are most appropriate for your case before starting an exercise regimen.

Modify Your Diet

Making changes to your diet is one of the key ways you can control your blood sugar level. A healthcare provider or registered dietitian can work with you to determine what modifications might be necessary. However, you want to eat a mixture of healthy food options such as:

• Fruits

• Low-fat and nonfat dairy

• Nonstarchy and—in limited quantities—starchy vegetables

• Protein like lean meat, fish, eggs, and nuts

• Whole grains

While eating from a variety of food groups, pay attention to your carb intake. Carbs are a main glucose source and affect your blood sugar more compared to other foods like fats or proteins. While you don't have to give up carbs, eating them in lower quantities can have a positive effect on A1C levels. Research has suggested that a low-carbohydrate diet may be beneficial for individuals with diabetes.

One study found that, after six months, people with diabetes who follow a low-carb diet had lower A1C levels compared to those who continued their usual diet. The researchers concluded that sustaining this diet could be a recommendation for people with type 2 diabetes, but further research would be needed.

Take Prescribed Medications

Physical activity and diet changes play a role in decreasing blood glucose levels. However, many people may also need to take medication for lower A1C levels.

For example, one medication that helps decrease blood sugar levels is metformin. It lowers the amount of liver-produced glucose and makes muscle more insulin-sensitive. Other types of medications called DPP-4 inhibitors—such as alogliptin (Nesina) and sitagliptin (Januvia)—improve A1C but don't result in hypoglycemia.

Even if your A1C falls at the appropriate level for you, you still need to continue taking medications as prescribed. Don't stop taking medications on your own. Talk with a healthcare provider if you have problems with your medicines for diabetes or other health conditions.

A Quick Review

A1C refers to a blood test that measures the average blood glucose levels within a two-to-three-month timeframe. It's a recommended test for managing diabetes but is also used in diagnosing people with type 2 diabetes or those at risk for prediabetes.

Factors such as exercise, stress, or certain health conditions can affect A1C. Talk to a healthcare provider about your A1C levels and develop a personalized treatment plan that helps you control your blood sugar levels.

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